Are you sure about that? That seems like a heckuva lot to put on a mobo header. Most mobos are 1amp, maybe a bit more, max (I thought, at least...I could be wrong.) If I'm not entirely off-base I think you could burn out the header. Those AP30s need 1.35A to start...I'd be careful about hooking them up to a mobo.
The Rheosmart only uses the PWM signal to adjust resistance to the fans. So you would plug a 4 pin Molex into the Rheosmart, and the PWM signal from the mobo.
The PWM signal tells the Rheosmart how much the power from the Molex to the fans is to be undervolted.
You can have the option to return the tach signal to the PWM header, so as to have full control of the fans from the mobo/speedfan/BIOS.
Or you could simply push a button on the Rheosmart to get manual control of the fans..... but when the mobo controls the fans perfectly, I don't know why anyone would want the manual option.
Have a look at Martin's review of the Rheosmart 3 on his MLL site.
My next rig will have two 120.4 rads. Each rad will be equipped with 8 GT 2150 in push/pull with home made shrouds on both sides. That is 16 fans at 1.5 watt each and I will control them all with the Rheosmart 6 via the CPU_FAN header.
That will be about 3 fans per channel, so I'll still be keeping it under 5 watts per channel.
But I am going to train a slow silent fan onto the Rheosmart's heatsinks just to be safe.
I might try to upgrade the heatsinks too but I don't think that will be necessary.
You can also have a look in my recent threads for more info, Martin contributed to both threads:
Fan Undervolting / Noise / RPM ??
The Reosmart PMW controllers??
Edited by PepeLapiu - 5/31/11 at 6:57pm